The Simpson Strong-Drive SDWS TIMBER Screw (0.220 in. x 9 in., Interior, E-coat) is a heavy-duty structural wood fastener engineered for cross-laminated timber construction, mass timber assemblies, log-home construction, and general interior wood-to-wood fastening applications. Featuring a black E-coat electrocoated finish, a low-profile washer head, and a T40 6-lobe drive system, this large-diameter structural screw is built to deliver fast, reliable installation with less torque than comparable lag screws - making it a go-to choice for timber framing professionals and serious builders.

Key Features

• SawTooth Point - enables fast starts and reduces installation torque, eliminating the need for predrilling in most interior wood applications and speeding up the fastening process.
• Serrated Threads with 5-1/4 TPI - reduces splitting and material damage as the screw drives through dense timber, protecting structural integrity in cross-laminated and mass timber assemblies.
• Large Low-Profile Washer Head (0.760 in. diameter) - provides maximum bearing area and pulls members down firmly without requiring extra washers, saving time and simplifying the installation workflow.
• T40 6-Lobe Drive - creates positive bit engagement that makes driving easier, reduces cam-out, and extends bit life during high-volume timber framing work.
• E-coat Electrocoated Finish (Black) - provides a durable, consistent coating suited to interior structural applications, with a clean black appearance that blends with exposed timber aesthetics.
• 3 in. Thread Length on a 9 in. Shank - delivers deep, targeted thread engagement for strong wood-to-wood connections in thick timber members.
• Code Listed under IAPMO-UES ER-192 - meets 2018 and 2021 IRC and IBC code requirements for common wood framing applications, giving engineers and inspectors confidence in structural compliance.
• Includes T40 6-Lobe Driver Bit - ready to drive right out of the package, reducing prep time on the job site.

Why This Product

• Designed specifically for mass timber and CLT construction - the 0.220 in. shank diameter, SawTooth point, and serrated threads are engineered to handle the demands of cross-laminated timber and log-home fastening where conventional screws or lag bolts fall short.
• Faster installation with less effort - the SawTooth point and T40 6-lobe drive work together to reduce required torque compared to standard lag screws, so large timber jobs get done faster with less fatigue.
• Eliminates extra hardware - the oversized 0.760 in. low-profile washer head generates the bearing area of a traditional washer-and-lag combination in a single fastener, streamlining the connection and reducing component count.
• Code-compliant for structural confidence - IAPMO-UES ER-192 listing and IRC/IBC compliance means this screw can be specified and inspected with confidence for structural wood framing applications without additional engineering justification in covered scenarios.

Specifications

• Brand: Simpson Strong-Tie
• Coating: E-coat Electrocoating
• Finish: E-coat Electrocoating
• Color: Black
• Shank Diameter (in.): 0.220
• Length (in.): 9
• Head Diameter (in.): 0.760
• Head Type: Low Profile Head
• Thread Length (in.): 3
• Thread Type: Serrated Threads
• TPI: 5 1/4
• Point Type: SawTooth Point
• Drive Type: T40 6-Lobe
• Country of Origin: Taiwan

Available Pack Options

• SDWS22900-R50: 50 Pk - includes T40, 6-lobe driver bit (replacement bit: BIT40T-134-R2)
• SDWS22900: 250 Pk - includes T40, 6-lobe driver bit (replacement bit: BIT40T-134-R2)

Approved Applications

• Fastening Wood-to-Wood
• Log-Home Construction

Frequently Asked Questions

Do I need to predrill before installing this timber screw?

In most interior applications, predrilling is not required. The SawTooth point is specifically designed to ensure fast starts and reduce installation torque, allowing the screw to self-start in wood without a pilot hole in the majority of common timber fastening situations.

Is this screw suitable for outdoor or treated-lumber applications?

This version features an E-coat electrocoated finish and is rated for interior applications. For outdoor or pressure-treated lumber environments, a corrosion-rated variant would be appropriate. Always verify finish compatibility with your specific application requirements.

What code listings does this timber screw carry?

This screw is code listed under IAPMO-UES ER-192 and meets 2018 and 2021 IRC and IBC code requirements for several common wood framing applications, making it suitable for use in code-inspected residential and commercial timber construction.

What drive bit does this screw use, and is one included?

This screw uses a T40 6-lobe drive. A T40 6-lobe driver bit is included in the package. If a replacement bit is needed, the compatible replacement is the BIT40T-134-R2.